1.7 water

Question 1

what is water

Answer 1

a major component for cells

Question 2

explain how hydrogen bonds form between water molecules

Answer 2

water is a polar molecule so has slightly negatively charged oxygen atoms which attract slightly positively charged hydrogen atoms of other water molecules

Question 3

what are the 5 properties of water

Answer 3

• metabolite
• solvent ( can dissolve solutes )
• high specific heat capacity
• high latent heat of vaporisation
• strong cohesion between water molecules

Question 4

what is the importance of water being a metabolite in biology

Answer 4

it is used in condensation/hydrolysis/photosynthesis/respiration

Question 5

what is the importance of water being a solvent in biology

Answer 5

• allows metabolic reactions to occur ( faster in solution )
• allows transport of substances eg. nitrates in xylem, urea in blood

Question 6

what is the importance of water having high specific heat capacity in biology

Answer 6

• buffers changes in temperature as can gain/lose a lot of heat/energy without changing temperature
  1. good habitat for aquatic organisms as temperature more stable than land
  2. helps organisms maintain a constant internal body temperature

Question 7

what is the importance of water having high latent heat of vaporisation in biology

Answer 7

allows effective cooling via evaporation of a small volume ( eg. sweat ) so helps organisms maintain a constant internal body temperature

Question 8

what is the importance of water having strong cohesion between water molecules in biology

Answer 8

1. supports columns of water eg, transpiration stream through xylem in plants
2. produces surface tension, supporting small organisms to walk on water